An Overview of Autism and Possible Causes
For years, most people thought of autistic children as
people who could barely talk, who banged their heads on the wall in a repetitive
motion and who were extremely mentally retarded. Today, we’ve learned so much
more. Perhaps the biggest change in our knowledge is that there is an extremely
wide range of behavior that can be classified as autistic. So much so that many
researchers now prefer to call it “autism spectrum disorder, (ASD)” because
cases range from very mild to severe. There are some children with ASD who are
very mentally retarded and need to go to special schools, but other ASD kids can
go to regular schools (and get special education services), speak completely
intelligibly, learn to read, etc. About 70 percent of kids with ASD are mentally
retarded to some degree. But a small percentage of ASD children eventually seem
to recover completely and go on to lead normal lives.
The hallmark of autism is that people who have it always
experience some level of difficulty relating to other people, understanding the
emotions and feelings of others and “reading” facial expressions. They are
unable to pick up on the subtle clues that allow people to feel empathy for
others and to act appropriately in society. They simply do not blend in easily
in the world, so even if they’re not mentally retarded, they may not be able
to hold down a job or live independently.
What do we know
about the cause of autism?
Earlier, researchers thought that autism was caused by the
way a child was raised. There even used to be a term—“refrigerator
mothers”—that some researchers used to describe the parenting style of women
who had autistic children. The theory was that children with autism had cold,
distant mothers who withheld love and affection. Part of that may have stemmed
from the fact that autistic children often have “flat” personalities, and
they seem indifferent to cuddling or other affectionate behaviors.
Now, experts believe that autism is caused by an interplay
of genetic and environmental factors. While nobody knows the cause, in the past
decade researchers have identified several factors that they hope will
eventually explain why autism occurs and that may provide new treatments. For
example, children with autism have:
brains than normal children.
outer zones of white matter in proportion to the rest of the brain
gray matter and a larger cerebellum in proportion to the rest of the brain
brain cerebral cortex and hippocampus
stacks of neurons in the brain; these stacks are also greater in number and
more uniform than in normal brains.
Additionally, children with autism generally focus on
different points in a setting than people who don’t have autism. For example,
if you show a scene from a movie in which several people are having a
conversation, normal people would focus on watching the characters who are
talking. But someone with autism may focus instead on something completely
different, such as a doorknob.
Even though researchers have learned these things about the
brains of people with autism, they still really don’t know why these
abnormalities cause the condition. But the hope is that eventually, all of the
clues will uncover the cause and lead to new, improved treatments.
In terms of causes, there is no evidence that vaccines are
contributors, although some of the more radical autism groups continue to
believe that vaccines may have something to do with the condition. There are
also some researchers who believe that food allergies may play a role.
Additionally, it seems that genetics are a factor. Parents who have one child
with autism are at a 100 times increased risk of having another child with
autism. And in twin studies, if one identical twin has autism, the other twin
has a 60 to 85 percent chance of having it as well.
Institute of Mental Health; The New York
Times, Science Times Section, “Lifting the Veils of Autism, One by One,”
24 February 2004;